Pneumatic rotary motor



ocr. 23, 193:4;

R. A NoRLjNG 'PNEUMATIC ROTARY MOTQR original' Filed Nov; 1o,- 1927 s yshetsf-slwet 1 lllll-lllll III? Il. l l

Ajail" 1,977,691 ienaUMATxc normar Moron Reinhold n. Norling, Aurora, Ill., assigner to independent Pneumatic Tool Company, Chicago, mi., a corporation of Delaware Appiication November liti, 1927, Serial No. 232,289 Renewed November 5, 1932' d @latina ((Cl. lill- 34) In my copending application Serial No. 169,691, is carried by the extension 2 over the upper porled February 21, 1927, I have shown, described, tion of the grinding wheel 4, as shown. A casing and claimed a pneumatically operated rotor for 6 surrounding the governor mechanism of my driving the spindle of `a portable pneumatic roinvention is secured to the rear end of the casing il tary tool, the rotor being provided with a multi- 1, and the grip handle 7 of the tool is secured to oo plicity of peripheral recesses or pockets which as the casing 6. e they pass the inlet and exhaust ports of the tool 'Ihe motor casing 1, as shown in Fig. 2, contains control the admission and exhaust of motive iluid the rotor mechanism of the tool, and this mechto and from the rotor casing, and thereby make anism` includes a shaft 8 which extends 1ongi 10 it possible to keep the timing accurate whether tudinally through the central portion of said o5 the rotor runs fast or slow, casing. The ends of the shaftp project beyond A The object of my present invention is `to emthe Opposite endsv of the casing 1 and are there ploy in connection with that or any other type lournaled in eenlifrietienelbeerings 9, 10, Which of'rotor means icr automatically regulating the are supported by end plates-11, 12, which close 1e supply of motive duid to the rotor casing dependthe opposite ends of the casing 1 and are Sup- 7o ing on the speed of its rotations and thereby cut Ported in glOOVeS r recesses, Provided in the down the supply when the tool is idle ond perends of the casing, as shown. These plates have forming no work, whilegiving a i'ull supply oi Centrally diSDOSed annuler VHeiligesv 13, 14 which motive fluid to the tool when Work is being per- Surround the bearings 9, and Support the Same.

formed. The shaft 8 has a flexible connection with the 75 The means shown in the present application ,Spindle 3 lUSl'f beyond the bearing 9 by e Star C011- for accomplishing this purpose comprises a valve Bling Which has right-angular diSDOSedlOngueS means for oontroning the Supply of motivo fluid tting in slots in the adjacent ends of the shaft to the rotor and a governor device rotated by and Spindle. iespeeiivelylHere the extensionl 2 the rotor for automatically controlling the open- Carries an enliflletin bearing 15`t0 SUDDOlt the 30 ing and closing movements of said valve means -lOlned endS 0f the Shaft end Spindle, eS SllOWn in accordance with the speed of rotation of the in Fig-'l rotor. Located in the casing 1 is a. cylindric rotor 16 The invention consists further in the matters lWliieh iS keyed 0r otherwise xed on'the shaft 8 ao hereinafter described and maimed. S0 es t0 rotate the Same The inner Surface 0f sa In the accompanying drawings... the casing 1 is shaped to have two eccentric por` Fig, 1 is a side elevational view of 9, portable tions 17, 17, which curve outward from rotor 16 pneumatic rotary tool, suon as a, grinder, on opposite sides thereof, and two concentric equipped with a governor controlled valve in acportions 13, 13. Which beer against the' outer ooi-dance with' my invention; perpiheral portion of the rotor between the eccengo Fig. 2 isan enlarged longitudinal vertica1 seotric portions and thus enable theI rotor to divide tional view taken through the tool to show the the eccentric DOItiOnS from each Other and form governor controlled valve; pressure chambers 19, 19 therewith to receive the Fig. 3 is a similar View through the same parts radial bladesZO, 20 which are slidably carried by 1o te show other deteus of the structure; the rotor 16 in radial slots 21. 21 therein. The o5 Fig. 4 is a vertical sectional view through the bledeS 20 and the SlOS 21 extend the full length governor and valve mechanism; of the rotor 16 with the end plates 11, 12 closing Fig. 5 is a vertical sectional view through the the ends 0f thefSlOtS and also providing end bearrotor section of the too1 teken on line 5 5 of ins surfaces for the blades. as Shown in Fig. 2.

Fm 2; and The depths of the slots 21 are slightly greater 100 Fig, 6 is a sectional view taken on line 6 5 than the Width of the blades so as to provide of Fig. 4, spaces at the bottoms'of the slots beneath the The tool Shown in the drawings is in the form blades to receive live or compressed air or other of a portable pneumatic l grinder, which has a motive uid employed fOr holding the blades out motor casing 1 with a tubular extension 2 secured against the inner surface of the casing 1 as the 105 to the front end of the casing and extending forrotor 16 revolves. 'I'he manner in which live air ward therefrom. 'I'he spindle 3 of the tool is lois supplied to the bottoms of the slots for this cated in the extension 2 and has a grinding wheel purpose will be presently described. The rotor or disc 4 secured to its outer end beyond the ex- 16 is cored or bored out to lighten it. l tension 2, as shown in Fig. 1. A. safety guard 5 The rotor 16 is provided with a multiplicity of 110 peripheral pockets or recesses 22. These are arranged in rows extending circumferentially about the rotor in the spaces between the blades with the recesses of one row offset laterally with those of an adjacent row and staggered with respect thereto, as shown in Fig. 3. The blades 20 always outnumber the pressure chambers 19, whether one or more, so that the rotor will always have a driving torque on the shaft 3 when in operation.

For each pressure chamber 19, the casing l is provided with inlet and exhaust ports 23, 24 arranged adjacent the opposite ends of the chamber and opening through the concentric and eccentric portions 17 and 18, respectively, of the casing, as shown in Fig. 5. The inlet ports 23 for each chamber 19 are equal in number to the `rows of peripheral recesses 22 in the rotor 16,

and said ports are disposed to provide a port for each row of recesses, as shown in Fig. 3. The inlet ports 23 for each chamber 19 are arranged in a row longitudinally of the rotor and are supplied with live air through passages 25 formed in the casing 1 along the rows of the respective ports. As shown in Fig. 5, the inlet ports' 23 are arranged at an angle to their respective passages 25 and are so disposed as to admit live air into the rotor casing through the peripheral pockets 22 in the general direction of rotation of the rotor so that the force of the incoming air in striking the walls of the pockets will be in a direction to assist in turning the rotor. As shown in Fig. 3, the inlet ports 23 in each row are also arranged at an angle to 'the axis of the rotor with the ports on opposite sides of the center of the rotor discharging toward the opposite ends of the rotor. This arrangement permits drilling of these ports through the opposite ends of the rotor casing in the manufacture of the device.

'I'he exhaust ports 24 are preferably in the form of slots made in the casing 1 at opposite ends of the same and connected by passages 26, 26, which are substantially parallel, as indicated in Fig. 5.

-The end plate 11 is cut away at the slots 24 and thus opens the exhaust ports to an annular exhaust chamber 27 in the end of the extension 2 where it is secured to the motor casing 1. This chamber is provided with a number of exhaust ports 28, 28 which connect the chamber with the atmosphere, as shown in Fig. 2. These ports' 28' are arranged at an angle so that the exhaust air is directed toward the forward end of the tool and thus away from the operator.

At each eccentric portion 18 are a set o the inlet and exhaust ports 23, 24, such ports being for the pressure chamber 19 on opposite sides of the eccentric portion. These ports are so spaced that the distance between their nearest edges where they open through the inner surface of the casing 1 is slightly greater than the circumferential length of a recess or pocket 22 in the periphery of the rotor 16. This makes each recess 22 shorter than the distance between these ports so that the inlet ports will not beV connected with the adjacent exhaust port to lose live air through the latter as the recesses pass between them in the rotation of the rotor 16. With the recesses 22 in the rotor opening and closing the inlet ports 23 as the recesses pass them, no valve mechanism is required as the rotor itself in addition to being the piston element of the motor also serves as the valve therefor. Operating n. this principle it is possible to keep the timing accurate Whether the rotor runs fast or slow.

The handle 7 has a live air inlet passage 29 to the outer end of which is connected the air supply hose (not shown) as in tools of this general character. A self closing throttle valve 30 controls the passage of air from the lower to the upper portion of vthis passage. Said valve is slidably mounted in a sleeve 31 which has port holes 32, 33 on opposite sides of the seat of the valve. These port holes connect the lower and upper portions, respectively, of the passage 29 when the valve 30 is manually moved and held off its seat by the trigger 34. The upper end of the passage 29 opens into a chamber 35formed in the portion of the handle opposite the casing 6. The handle 7 is provided with a pair of pas sages 36, 36 (Fig. 3) which open at their inner ends into the chamber 35 on opposite sides of the same. These passages open at their outer ends into passages 3.7, 37 in the section 6. The passages 37 open through ports 38 in the end plate 12 into the main supply passages 25 for the inlet ports 23 for the rotor 16, as shown in Fig. 3. The passages 37, 37 are on opposite sides of the valve casing 6 so as to be positioned for the pas-y sages 25 for the two sets of inlet ports 23.

A plate member 39 is set in a recess 40 in the face of the handle 7 where it is clamped against the'casing 6. The-plate 39 is held in this recess by having its outer marginal portion overlapped by the section 6. 'I'he plate 39 is provided with two sets of laterally extending webs or lugs 41, 42. These webs extend into the chamber 35 with the web 41 extending directly over the end of the passage 29 where it enters said chamber. This web is provided with three apertures or port openings 43, 43, all of which register with the passage 29, its associated end being large enough to take in all of the ports. The upper web 42 is bifurcated to provide ears between whichl is pivoted a swinging valve member 44 for opening and closing the openings 43. The lower end of this valve member is made long enough so as to take in all of the openings 43 and thus open and close the same simultaneously.

The end of the rotor shaft 8 at the end plate 12 is bored out, as at 45. A member 46 is screwed 120 into the outer end .of the bore 45, and has an enlarged head at its outer end which is provided with a pair of outwardly projecting parallel flanges or webs 47, 47, between which are pivoted weights 48, 48. These are arranged on opposite sides of the longitudinal axis of the rotor shaft 8 and have projections 49, 49 at their inner ends and which projections lie beneath a head 50 at the outer end of a rod 5l, which is slidably mounted in the support 46. The inneriend of the rod 51 extends into the bore 45 and there carries an enlargement which may be in the form of nuts 52, 52 screwed on such end of the rod. A coiled spring 53 surrounds the portion of the rod between these nuts and the adjacent end of the support 46, the spring thus serving to constantly draw the rod into the bore 45.

The valve member 44 is slotted between its ends, as at 54, and in this slot is located a block 55, which is trunnioned or pivoted to the valve member in the slot by a pin 56. The block 55 has a stern 57 which extends on opposite sides of the block. The inner portion of the stem 57 extends through the center of the plate 39 and has its inner end in alignment with the rod 51 so that, when said rod is moved outward by the outward movement of the weights 48 by the centrifugal forces set up in rotation of the rotor, therrod 51 will engage the stem 57 and swing the valve member 44 over the ports 43 and thus reduce the when the rotor is passage 61 opens into a duct 63 which opens into.

amount of live air supplied to the 'rotor as the speed of rotation of the rotor increases. 'Ihe outer end of the stem 57 will contact with the opposed wall of the chamber 35 when the valve member 44 is in fully closed position, and thus act as a stop therefor. As the speed decreases, as under heavy load, the spring 53 overcomes the centrifugal action on the weights 48 and draws them toward each other and at the same time draws therod 51 away from the stem 57, therebyallowing the valve member 44 to be swung back into its position fully Aopening the ports 43 and thus supply the full amount of live air tothe rotor, as is required at this time. This opening movement of the valve member is caused by the live air pressure on the end of the stem 57 plus the action of a coiled spring 58 on the block 55. By making the rod 51 and the stem 57 separate from each other, the rod may be carried around with the rotor without affecting the stem 57 or the valve member 44, which are non-rotative with respect to the rotor.

The section 6 is made hollow to provide an oil or lubricant containing chamber 59, which has an outlet 60 opening into a passage 61. The amount of lubricant allowed to flow out of the opening 60 is regulated by a needle valve 62.- 'I'he the upper portion of the main air supply passage 29 in the handle. By this arrangement, the air in passing through the passage 29 over the adjacent end of the duct 68 acts to draw lubricant from the chamber 59 into the passage 29, which lubricant is picked up by the flowing air and deposited on the moving parts of the `tool for lubricating them.-

To constantly supply live air to the under side of the blades 20 so as to hold them out against the inner surface of the casing 1, I provide annular grooves 64, 64 in the inner faces of the end plates 11 andv 12, respectively. These grooves extend completely around the plates and are disposed opposite the inner ends of theslots 2l. The lower corners of the blades 20 are beveled or chamfered off, as shown, so as not to close the grooves when the blades go to the full depth of their respective slots. Passages 65, 66 in the respective end plates 11, 12 connect the grooves 64, 64 with the main air supply `passages 25, 38, respectively, of the tool, so that there is a constant supply of live air to the under sides of the blades. The passage 65 opens into one of the ports 38, while the passage 66 is connected with one of the inlet passages 25, as shown in Fig. 3.

To hold the rotor 16 against end play and thus eliminate friction on the end plates 11 and 12, I extend the bearing support 14 beyond the bearing assembly 1 0 and provide said support with internal screw threads to accommodate an externally threaded clamp ring 67, as shown in Figs. 2 to 4. .This clamps the outer ring 10H of the bearing against the end plate 12 to prevent lateral movement of said outer ring. The inner ring 10b of the bearing is clamped by the head of the member 46 against a shoulder 8a on the shaft 8 to hold the inner ring against lateral movement on said shaft. This construction, through the balls of the bearing fitting in grooves or raceways in the opposed faces of the rings, holds the shaft 8 against endwise movement and thus eliminates end play oi the rotor 16. Thus the rotor can not be forced against either end plate 11 or 12 by the air pressure which may act on either end of the rotor. The advantage of holding the rotor against endwise movementwill be apparent when it is considered that only 4slight clearances are allowed between the rotor and the adjacent end plates in portable tools to which this invention is particularly applicable. 'I'hese tools, being portable, are likely to be held in various positions when handled and while in use and with the slight clearances provided between the'rotor and the end plates, the rotor could, if not held against endwise movement, quickly contact with the end plates because of the small clearances provided in the construction. The. clearance is only approximately .0025 of an inch. Thus slight movement'of the rotor if permitted would cause it to rub against the end plates. The moment the rotor touches an lend plate, the pressure fluid is entirely on the opposite end of the rotor, pressing it against the opposed end plate. It is therefore absolutely necessary for an eillcient tool that the rotor should not rub against the end plates, and a practical ,way of holding the rotor against endwise movement for this purpose is by one of the bearings as hereinvdescribed.

The details of structure and arrangement of parts shown and described may be variously changed and modified without departing from the spirit and scope of my invention.

I claim as my invention:

1. In a pneumatic tool, a rotor casing, a rotor therein, a handle at one end of the casing and having a passage for the supply of motive fluid to the rotor for rotatingthe same, said handle having a chamber in said passage, a member f1tted in said chamber and closing the same toward the rotor, said member having a pair of spaced webs lextending into said chamber with one web over the passage where it enters the chamber and having a plurality of port holes over said passage, a valve member swingably mounted on the other web for opening and closing theport holes simultaneously, an operating stem for said valve member and extending therefrom toward the rotor through said fitting, and a governor device `interposed between the handle andthe rotor and rotated by the rotor for automatically controlling the opening and closing movements of the valve member through its stem in accordance with the speed of rotation of the rotor.

2. In a portable pneumatic rotary tool, a shaft, a rotor fixed thereon, means whereby motive fluid may be supplied to the rotor for rotating the same, a swingable valve for controlling the supply of motive fluid to the rotor and having a stem extending toward the same, a member screwed into said shaft and having an enlarged head at its outer end, an endwise movable rod extending through said member in line with said stem and having an enlargement at its outer end, weights pivotally mounted on said head on opposite sides of said rod and having inwardly projecting parts to engage beneath the enlargement for moving the rod against the stem to close `the valve in the outward swinging of the weights, and spring means at the inner end of the rod and acting to move the rod in the opposite direction to return the weights to their normal positions 4and allow the valvemember to open as the speed of the rotor decreases.V

3.. In a pneumatic tool, a rotor casing, a'rotor therein,'a handle at one end of the casing and having motive fluid supply passages therein, said 'handle vhaving a chamber'into` which said passages open, a section clamped between the handle and the rotor casing and having passages connecting those of the handle with those of the rotor casing for supplying'motive fluid thereto,J

a plate member clamped over said chamber by said section and having a web extending into the chamber over one of thehandle passagesl where it enters the chamber, said web having a plurality of port holes therein, a valve member swingably mounted on said member for opening and closing the port holes simultaneously, and a governor device in said section and rotated by the rotor for automatically controlling the opening and closing movements of the valve member in accordance with the rotor speed.

4. In a. fluid actuated rotary motor, a casing having a rotor chamber to be connected with a source of pressurel fluid supply, plates supportedby the casing and closing the opposite ends of the chamber, a rotor in the chamber between.

said plates and having shaft extensions extending through openings in the plates, said rotor having radial slots extending lengthwise thereof and opening through the periphery and the ends of the rotor, blades slidably mounted in said slots and extending substantially the full length thereof, said plates having inlet passages connected with the fluid pressure supply and discharging into the chamber toward the ends of the rotor and in line with the bottoms of the vest,

-members'and interposed bearing elements, the

inner ring member fitting on the shaft extension against a shoulder thereon. the outer ring member tting in the support against the plate at the inner end of the support, and non-yielding clamping members, one adjustably secured to the outer end of the shaft extension and engaging the inner ring member for clamping it against said shoulder on the shaft extension and the other clamping member being adjustably secured within the support on the outer side of the outer ring member for clamping the same against the plate at the inner end of the support to hold the rotor against end'ise movement in opposite' directions under the action of the pressure fluid against its ends to prevent rubbing of the rotor against the plates.

' REINHOLD A. NORLING. 

